sEMMC limitations

When working with sEMMC, you should be aware of the following limitations.

v0.1.1

Refer to the following detailed descriptions of current limitations:

• sEMMC does not support octal-lane data transmissions.

• sEMMC does not support dual data rate, and as such no support for HS400.

• nrf_semmc_config_t.read_delay can not be equal to or higher than the clkdiv parameter in sEMMC and FLPR counters.

• clkdiv parameter in sEMMC and FLPR counters must be even.

• Maximum frequency is limited to 80MHz on nRF54H Series (assuming a maximum device frequency of 320MHz, in HS200 mode) and 32MHz on nRF54L Series devices.

• A tuning cycle using CMD21 might be needed to set the proper value of nrf_semmc_config_t.read_delay.

• Data buffers and response buffers needs to be pointers with a 32-bit aligned address.

• nrf_emmc_data_t.block_size needs to be minimum 4 bytes for quad-lane data transmissions.

• Setting nrf_semmc_config_t.process_response to NRF_EMMC_RESPONSE_PROC_IGNORE will only apply to any transaction in the read direction.

• sEMMC is not able to process response and data at the same time. See for example Read responses on how to mitigate this.

• Any prepared transfer with nrf_semmc_cmd_prepare() will be discarded when using nrf_semmc_disable().